Heat exchanger arrangement

ABSTRACT

A heat exchanger arrangement for charge air cooling having a first heat exchanger and a second heat exchanger, through which a first fluid requiring cooling flows in such a way that the first heat exchanger is located ahead of the second heat exchanger in the flow direction of the first fluid. A first coolant flows through the first heat exchanger and a second coolant flows through the second heat exchanger in such a manner that the first heat exchanger cools the first fluid to a first temperature and the second heat exchanger cools the first fluid from the first temperature to a second temperature that is lower than the first temperature, wherein the first heat exchanger and the second heat exchanger can be formed as one structural unit.

This nonprovisional application claims priority under 35 U.S.C. §119(a) to German Patent Application No. 10 2012 202 234.1, which was filed in Germany on Feb. 14, 2012, and which is herein incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a heat exchanger arrangement, in particular for charge air cooling, having a first heat exchanger and a second heat exchanger, through which a first fluid requiring cooling flows in such a way that the first heat exchanger is located ahead of the second heat exchanger in the flow direction of the first fluid.

2. Description of the Background Art

In motor vehicles with supercharged engines, charge air cooling is critical for the ability to reach a high engine output. To this end, charge air coolers are used as heat exchangers in motor vehicles, wherein in the past, primarily air-cooled charge air coolers were used in the cooling module in the vehicle front. Recently, the proportion of coolant-cooled charge air coolers is increasing, which has the advantage that the coolant-cooled charge air cooler no longer has to be located in the cooling module, but instead can also be located elsewhere in the engine compartment, for example can be flange-mounted directly to the motor.

However, coolant-cooled charge air coolers have the disadvantage as compared to air-cooled charge air coolers that the coolant typically has a higher temperature than the air for the air-cooled charge air coolers, so that the temperature reduction in coolant-cooled charge air coolers is generally less than is the case in air-cooled charge air coolers.

Moreover, demand for charge air cooling has increased ever further in recent times because the charge air temperatures are also continuing to rise ever higher on account of the ever increasing supercharging of the engines, so that greater cooling output becomes necessary to cool the charge air to lower temperatures.

Moreover, demands continue to be placed on pressure loss of the charge air in charge air coolers as well as the ever-growing demands for reduced installation space, so that this, too, is disadvantageous for achieving the ever increasing cooling outputs.

In addition, charge air coolers with two stages have become known from DE 41 14 704 C1, in which a high-temperature circulating system and a low-temperature circulating system are provided for cooling the air in two stages.

However, the arrangement of two-stage charge air coolers causes the problem that in an arrangement of multiple heat exchangers with simultaneous flow of coolants at different temperatures, high stresses arise as a result of thermal expansion, and can result in uncontrolled damage to the heat exchangers because of the frequently changing thermal loads.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a heat exchanger arrangement according to the preamble of claim 1 that is improved over the prior art with regard to endurance, space requirements, and pressure drop.

In this design, a heat exchanger arrangement is created, in particular for charge air cooling, having a first heat exchanger and a second heat exchanger through which a first fluid requiring cooling flows in such a way that the first heat exchanger is located ahead of the second heat exchanger in the flow direction of the first fluid, wherein a first coolant flows through the first heat exchanger, and a second coolant flows through the second heat exchanger, in such a manner that the first heat exchanger cools the first fluid to a first temperature and the second heat exchanger cools the first fluid from the first temperature to a second temperature that is lower than the first temperature, wherein the first heat exchanger and the second heat exchanger are implemented as one structural unit.

It is advantageous in this design if the first heat exchanger has an inlet box and an outlet box for the first fluid and a heat exchanger core located therebetween, wherein the second heat exchanger is located in the outlet box of the first heat exchanger or is located after the outlet box of the first heat exchanger.

In another exemplary embodiment, it is useful if the second heat exchanger has an inlet box and an outlet box for the first fluid and a heat exchanger core located therebetween, wherein the first heat exchanger is located in the inlet box of the second heat exchanger or is located ahead of the inlet box of the second heat exchanger.

It is also useful if the first heat exchanger has an inlet box and a first heat exchanger core and the second heat exchanger has a second heat exchanger core and an outlet box for the first fluid, wherein the two heat exchanger cores are accommodated in a common housing or each have a separate housing or are accommodated in one housing and/or are connected to one another by means of a connecting element.

According to another concept of the invention, it is advantageous if the first and/or the second heat exchanger core is a shell and tube heat exchanger core with a bundle of tubes through which the first fluid can flow, the ends of each of the tubes being accommodated in openings of a tube base, wherein the first or second coolant can flow around the tubes.

Also, it is useful if the inlet box of the second heat exchanger and/or the outlet box of the first heat exchanger has an opening in which the first or second heat exchanger is placed.

In this context, it is advantageous if the first and/or the second heat exchanger core is a shell and tube heat exchanger core or plate heat exchanger core, with a bundle or stack of tubes or plates, wherein the first fluid can flow around the tubes or plates and wherein the first or second coolant can flow through the tubes or plates.

It is also advantageous if the inlet box of the second heat exchanger and/or the outlet box of the first heat exchanger has an opening in which the first or the second heat exchanger is placed.

Furthermore, it is advantageous if the heat exchanger placed in the opening has, on one side, a header box that projects at least partially out of the opening and has at least one connection for a coolant.

Also, it is useful if the outlet box of the first or of the second heat exchanger represents a manifold of the cylinder head or can be connected with such a manifold.

Additional advantageous embodiments are described by means of the following figure description and by the dependent claims.

Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein:

FIG. 1 is a schematic representation of a heat exchanger arrangement according to the invention with two stages for cooling a fluid, in particular charge air,

FIG. 2 is a schematic representation of a first heat exchanger, in particular for the first stage,

FIG. 3 is a schematic representation of a first heat exchanger, in particular for a first stage,

FIG. 4 is a schematic representation of a first heat exchanger, in particular for a first stage, in an exploded view,

FIG. 5 is a schematic representation of a second heat exchanger, in particular for a second stage,

FIG. 6 is a schematic representation of a second heat exchanger, in particular for a second stage,

FIG. 7 is a schematic representation of a second heat exchanger, in particular for a second stage,

FIG. 8 is a schematic representation of a second heat exchanger, in particular for a second stage,

FIG. 9 is a schematic representation of a heat exchanger arrangement according to the invention with two heat exchangers for two-stage cooling of a fluid, such as charge air in particular,

FIG. 10 is a heat exchanger arrangement according to FIG. 9 in a perspective view,

FIG. 11 is a block of tubes with tube bases of a heat exchanger core, and

FIG. 12 is a schematic representation of a heat exchanger arrangement according to the invention with two heat exchangers for two-stage cooling of a fluid, such as charge air in particular.

DETAILED DESCRIPTION

FIG. 1 shows a heat exchanger arrangement 1 having a first heat exchanger 2 and a second heat exchanger 3 through which flows a first fluid 4 requiring cooling, such as charge air. For this purpose the arrows 5 and 6 are used to identify the inflow of the fluid 4 into the inlet box 7 of the first heat exchanger and the outflow of the first fluid 4 out of the outlet box 8 of the first heat exchanger.

The first heat exchanger 2 is thus composed of an inlet box 7 and an outlet box 8, with a heat exchanger core 9 being arranged between the inlet box 7 and the outlet box 8; the first fluid 4 flows through the heat exchanger core.

In the exemplary embodiment from FIG. 1, the first heat exchanger core 9 is implemented as a shell and tube heat exchanger core, in which a plurality of tubes 10 are connected at their ends to tube bases 11 and 12 in a fluid-tight manner, so that the inflowing fluid 4 can flow from the inlet box 7 through the interior of the tubes 10 to the outlet box 8, while the tubes in the tube bundle are accommodated in a housing 13 and a coolant can flow around them. For this purpose, the housing 13 has an inlet connection 14 and an outlet connection 15, so that the coolant 16 can flow into the inlet connection 14 as shown by the arrow 17 in order to flow around the tubes 10 and then can flow back out of the outlet connection 15, see arrow 18. Consequently, the first heat exchanger core 9 cools the inflowing first fluid 4 from an inlet temperature to a first temperature at which the first fluid enters the outlet box 8.

The second heat exchanger 3 is located in the outlet box 8. This heat exchanger 3 takes up essentially the entire cross-sectional area of the outlet box 8, so essentially the entire flow of the first fluid 4 out of the first heat exchanger core then subsequently flows through the second heat exchanger core 19 of the second heat exchanger 3 before it can emerge from the outlet box 8.

The first fluid 4 flows as indicated by the arrow 20 through the first heat exchanger 2, while the coolant flows in the opposite direction as shown by arrow 21, so there is a counterflow configuration.

The second heat exchanger 3 is arranged at right angles to the flow direction 20 of the first fluid so that the first fluid can flow through the heat exchanger in its full width perpendicular to the direction of flow of the fluid 22. In this design, the second coolant 23 flows through the inlet connection 24 into the heat exchanger 3, flows through the heat exchanger as indicated by the arrow 22 at right angles to the flow direction 20 of the first fluid, is redirected in the header box 25, for example in a U-shape, and then, as indicated by the arrow 26, flows back to the header box 27, whence it can flow out of the heater exchanger 3 again. As is evident, a flange 28 of the heat exchanger 3 sits in an opening 29 of the outlet box 8 and serves to cool the fluid from a first temperature at which it leaves the first heat exchanger to a second temperature that is lower than the first temperature.

The intake pipe 50 shown in FIG. 2 comprises an inlet box 51. This inlet box can be implemented as an injection molded plastic part. Alternatively, it can also be implemented as a metal part. The inlet box 51 tapers in cross-section in a width direction B of the intake pipe 50. At its lateral end with maximal cross-section, an inlet connection 52 for delivering a first fluid, such as charge air for example, is provided, for example is flange-mounted. The delivery is indicated by the arrow 53. The inlet box 51 essentially fulfills the function of an inlet-side header of a heat exchanger 54 adjoining the inlet section 1. The first fluid flows through the heat exchanger 54 in one direction as shown by arrow 55, wherein heat from the fluid is transferred to a first coolant in the form of a liquid coolant.

Located on the outlet side of the heat exchanger 54 through which the first fluid flows is an engine flange 56, which can be flange-mounted directly to a cylinder head (not shown) of an internal combustion engine. In the present case, the attachment is accomplished by means of seal faces 57 and mounting holes 58. The cross-sectional area of the opening of the engine flange 56 expands in the first fluid's direction of flow from the outlet of the heat exchanger 54 to the plane of connection of the cylinder head. The flange 56 in this design represents the outlet box of the heat exchanger, which can then direct the first fluid directly into the cylinder head of the engine.

In this design, the heat exchanger is composed of the inlet box 51, the outlet box 56, and the heat exchanger core 59, which is located between the two boxes 51, 56. The heat exchanger core 59 here is connected to the inlet box 51 and outlet box 56 by means of a flange 60, 61.

Through the heat exchanger core 59 flows a first coolant, which flows in through the connection 62, flows through the core 59, and flows out again at the connection 63. In this process, the first coolant flows as indicated by arrow 64, in counterflow to the flow direction 55 of the first fluid.

In the present case, the engine flange 56 is made as a die-cast aluminum part. However, it can also be made as a plastic part. It includes a connecting member 65 at a lateral region for a high-pressure exhaust gas recirculator, although the recirculator is optional and can be omitted.

The heat exchanger core 70 is shown in detail in FIG. 3 and in the exploded view in FIG. 4. It comprises a plurality of tubes 71 stacked in the width direction B, the tubes being designed as flat tubes. The wide sides of the flat tubes extend in the height direction H and depth direction T. The narrow sides of the flat tubes extend in the height direction H and width direction B. The illustration does not show turbulence inserts or ribs, each of which is arranged between the wide sides of adjacent flat tubes 71. They may also be areally soldered to the tubes.

In the present case, the flat tubes 5 are made from folded and welded sheet metal or are made as extruded flat tubes. Alternatively, they can also be made as extruded profiles. Depending on requirements, the flat tubes 71 may have embossed features facing inward or outward to generate turbulence and/or ensure a defined spacing of adjacent flat tubes during assembly. Alternatively or in addition to such embossed features, the interior of the flat tubes 71 can be provided with turbulence inserts or ribbed plates.

The ends of the flat tubes 71 terminate in openings 72 with or without pass-throughs of a tube base 73. The tube bases 73 are produced from an aluminum sheet as formed sheet-metal parts. It is advantageous for the inlet side and outlet side bases 73 to be identical in construction, reducing the number of different components.

The stack of flat tubes 71 is surrounded by a water jacket 74 that has a first water jacket section 75 and a second water jacket section 76. The water jacket 74 simultaneously forms a part of the housing of the intake pipe according to the invention, which is composed as a whole of the inlet section 51, the water jacket 74, and the engine flange 56.

The two water jacket sections 75, 76 each have a base 77, 78 with two angled legs 79 at the ends. Each of the bases 77, 78 extends in the width direction B at right angles to the flow direction of the first fluid, such as charge air, and is areally soldered to the narrow sides of the exchanger tubes 71. Each of the legs 79 covers a part of a wide side of the applicable outer flat tube 71 of the stack, and is areally soldered to this wide side.

Alternatively, the water jacket has two bases 77, 78 and two side parts 79 on the ends that are formed separately from the base. In this design, both the base and the side parts are essentially flat and form the four sides of a quadrilateral or box. Each of the bases 77, 78 extends in the width direction B at right angles to the flow direction of the first fluid, such as charge air, and is areally soldered to the narrow sides of the exchanger tubes 71. Each of the side parts 79 covers the wide side of the applicable outer flat tube 71 of the stack, and is areally soldered to this wide side.

Alternatively, the lateral leg can also cover the full area and be spaced apart from the flat tubes on the sides so that a housing is formed in the entirety of which flow can pass, thereby also making it possible for flow to pass around the outer flat tubes.

In order to join the tube bases 73 or the housing to the inlet or outlet boxes 51, 56 as shown in FIG. 2, circumferential rims 80 are provided at the tube bases 73 to serve as a flange for connection to the inlet and outlet boxes.

Each of the water jacket sections 75, 76 has, in the region of its base 77, 78, elongated convexities 81 extending in the width direction B that perform the function of a header for the liquid first coolant flowing around the flat tubes 71. Connections 82, 83 are provided at the convexities 81 of one water jacket section for delivering and removing the coolant. The convexities 81 on the second water jacket section shown at the bottom improve the distribution of the coolant, which as a whole flows largely in the height direction H, opposite to the direction of flow of the first fluid—charge air—along the wide sides of the flat tubes 71, which is to say in counterflow direction with respect to the first fluid. In alternative embodiments, the connections can also be provided on different sides of the water jacket.

The tube bases 73, together with the flat tubes 71 and the water jacket sections 75, 76, are mechanically preinstalled or fixtured and soldered into a heat exchanger block in a soldering furnace. To this end, suitable surfaces of the individual components are coated with solder.

In order to connect the inlet box and the engine flange as the outlet box, the bases have edges that are bent by 90°, which advantageously are provided with corrugated slot flanges. During assembly of the intake pipe according to the invention, corresponding structures on the sides of the inlet box and of the engine flange as the outlet box are joined in an interlocking manner to the corrugated slot flanges, so that a seal, not shown, is pressed in a sealing manner between the inlet box and the engine flange as the outlet box, on the one hand, and the applicable base on the other hand.

FIGS. 5, 6, 7, and 8 show schematic embodiments of heat exchangers that can be used as the first or second heat exchanger and that can be arranged in an inlet or outlet box. Here, each of the heat exchangers 101, 102, 103 has a heat exchanger core 104, 105, 106 and a first header box 107, 108, 109, as well as a redirecting chamber 110, 111, 112, wherein the one header box 107, 108, 109, and the redirecting chamber 110, 111, 112 are located at opposite ends of the heat exchanger in each case.

In this design, the header box 107, 108, 109 in each case has an inlet connection 113 and an outlet connection 114, so that a first or second coolant can flow into the header box through the inlet connection, flow through the heat exchanger core, and be redirected in the redirecting chamber, then flow through the heat exchanger core again and back into the header box, which is advantageously divided by a partition, and flow back out of the heat exchanger through the outlet fitting 114.

Each header is provided with a flange 115 that allows the heat exchanger to be placed in an opening in a housing, for example an inlet box or an outlet box, and be fastened in a sealed manner.

It is advantageous for a heat exchanger core in accordance with FIGS. 5 and 6 to be designed as a radiator core with tubes and ribs, wherein the tubes are fitted and fastened in a fluid-tight manner through openings in a tube base and a coolant flows through the interior of the tubes, wherein ribs or turbulence inserts are arranged between the tubes, so that a first fluid can flow at right angles to the direction of flow of the fluid through the tubes and flow around the tubes of the radiator core in order to flow through the heat exchanger.

FIGS. 6, 7, and 8 show exemplary embodiments of a heat exchanger in which the header box with the flange plate is located at a small lateral end of the heat exchanger, wherein the exemplary embodiment in FIG. 5 is an exemplary embodiment in which the header box with the flange plate is located at a relatively large lateral end region of the heat exchanger. Here, in FIG. 5 the flange plate is essentially located in a plane parallel to a plane of the tubes, while in FIGS. 6 to 8 the flange plate is located essentially in a plane oriented perpendicular to the plane of the flat tubes.

A heat exchanger from FIGS. 5 to 8 can thus easily be integrated into an opening of an inlet or outlet box from FIG. 1, so that the heat exchanger can constitute the second heat exchanger in the outlet box of the first heat exchanger.

FIG. 9 shows another exemplary embodiment of a heat exchanger arrangement 200 in which two heat exchanger cores 201 and 202 are accommodated in a housing 203. FIGS. 10 and 11 show this heat exchanger arrangement once again in a perspective view from outside and a heat exchanger core with tubes and tube bases.

In addition, FIG. 11 shows the heat exchanger core 201 as an arrangement of tubes 204 that are accommodated in openings in tube bases 205, 206, wherein turbulence inserts 207 are arranged between the tubes 204; a coolant flowing around the tubes flows through the turbulence inserts.

FIG. 12 shows a heat exchanger arrangement that is essentially composed of two heat exchanger cores essentially corresponding to FIG. 3 or 4 or heat exchanger cores similar thereto. Here, a first heat exchanger core 301 is arranged between an inlet box 302 and an intermediate element 303, wherein the second heat exchanger core 304 is arranged between the intermediate element 303 and the outlet box 305. The first fluid to be cooled flows as indicated by the arrow 306 through the inlet connection flange or through the inlet connection fitting 307 into the inlet box 302. Then it flows through the heat exchanger core 301. From there, it flows into the intermediate element 303, which serves as a coupling element. From there, the first fluid flows through the second heat exchanger core 304 and then out again through the outlet box 305 and the corresponding connection fitting 308 as shown by the arrow 309.

The heat exchanger cores have a housing with an appropriate cover 310, 311, wherein connection fittings 312, 313, 314 and 315 are provided for inflow and outflow of a first coolant for the first heat exchanger core 301 and for a second coolant for the second heat exchanger core 304.

As is evident, in each case the tube bases 316, 317, 318, 319 are located on both sides of the heat exchanger core 301 or 304, and serve to connect the heat exchanger core to the inlet box 302 or outlet box 305 and to the intermediate element 303. The connection is advantageously made by a corrugated slot flange.

Moreover, ribs on the charge air side (not shown) can be arranged in the tubes 204.

The inlet box 208 is designed as a funnel-like element with a tube connection fitting 209. The outlet box 210 is schematically shown as a box that widens, which can be connected to a cylinder head of the engine. As is evident, the housing parts 203 of the individual heat exchanger cores are connected to one another at the boundary, advantageously designed as a single part. Here, it can be especially advantageous for the housings or the housing 203 to be made as a single part from plastic. The housing structure can be essentially rectangular, wherein the surface can be designed with a rib-like structure to improve strength.

Also evident are connection fittings 211, 212, 213 and 214, which serve to admit and to discharge a first coolant and a second coolant into and out of the first heat exchanger core or the second heat exchanger core. To this end, the first coolant is admitted at the inlet 212, flows through the heat exchanger core and flows around the tubes 204 arranged there, and is discharged from the heat exchanger core at the outlet 211. The second coolant is admitted to the second heat exchanger core at the inlet 214 and likewise flows through the heat exchanger core and flows around the tubes 204 arranged there before being discharged from the heat exchanger core at the outlet 213. Flow thus passes through the two heat exchanger cores in counterflow as compared to the direction of flow of the first fluid, such as charge air.

The heat exchanger arrangement here is housed in a housing 203 as a plastic shell. The housing can also be made from plastic or alternatively from metal, such as aluminum for example.

The two coolants are separated by the seal 215 between the middle bases 216, 217 and the housing 203, so that no mixing of the circuits occurs.

With suitable construction, in which aluminum coolant jackets are soldered to the flat tubes and bases, the two tube bundles of the heat exchanger cores can also be welded directly to one another or connected by a mechanical connection, for example crimping or screws or adhesives, through a plastic or aluminum intermediate element as coupling element. An intermediate element that is sealed to both bases by elastomer seals has the advantage that, as a decoupling element, it can reduce thermal and vibrational stresses that can arise between the two components.

The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims. 

What is claimed is:
 1. A heat exchanger arrangement for charge air cooling, the arrangement comprising: a first heat exchanger; and a second heat exchanger, wherein the first heat exchanger and the second heat exchanger are configured such that a first fluid requiring cooling flows in such a way that the first heat exchanger is located ahead of the second heat exchanger in a flow direction of the first fluid, wherein a first coolant flows through the first heat exchanger and a second coolant flows through the second heat exchanger such that the first heat exchanger cools the first fluid to a first temperature and the second heat exchanger cools the first fluid from the first temperature to a second temperature that is lower than the first temperature, and wherein the first heat exchanger and the second heat exchanger are implemented as one structural unit.
 2. The heat exchanger arrangement according to claim 1, wherein the first heat exchanger has an inlet box and an outlet box for the first fluid and a heat exchanger core located therebetween, and wherein the second heat exchanger is located in the outlet box of the first heat exchanger or is located after the outlet box of the first heat exchanger.
 3. The heat exchanger arrangement according to claim 1, wherein the second heat exchanger has an inlet box and an outlet box for the first fluid and a heat exchanger core located therebetween, and wherein the first heat exchanger is located in the inlet box of the second heat exchanger or is located ahead of the inlet box of the second heat exchanger.
 4. The heat exchanger arrangement according to claim 1, wherein the first heat exchanger has an inlet box and a first heat exchanger core and the second heat exchanger has a second heat exchanger core and an outlet box for the first fluid, wherein the two heat exchanger cores are accommodated in a common housing or each have a separate housing or are accommodated in one housing and/or are connected to one another via a connecting element.
 5. The heat exchanger arrangement according to claim 1, wherein the first and/or the second heat exchanger core is a shell and tube heat exchanger core with a bundle of tubes through which the first fluid is adapted to flow, ends of each of the tubes being accommodated in openings of a tube base, and wherein the first or second coolant can flow around the tubes.
 6. The heat exchanger arrangement according to claim 5, wherein the inlet box of the second heat exchanger and/or the outlet box of the first heat exchanger has an opening in which the first or second heat exchanger is placed.
 7. The heat exchanger arrangement according to claim 1, wherein the first and/or the second heat exchanger core is a shell and tube heat exchanger core or plate heat exchanger core with a bundle or stack of tubes or plates, wherein around the tubes or plates the first fluid is adapted flow, and wherein the first or second coolant is adapted to flow through the tubes or plates.
 8. The heat exchanger arrangement according to claim 7, wherein the inlet box of the second heat exchanger and/or the outlet box of the first heat exchanger has an opening in which the first or the second heat exchanger is placed.
 9. The heat exchanger arrangement according to claim 1, wherein the heat exchanger placed in the opening has, on one side, a header box that projects at least partially out of the opening and has at least one connection for a coolant.
 10. The heat exchanger arrangement according to claim 1, wherein the outlet box of the first or of the second heat exchanger is a manifold of the cylinder head or is connectable with the manifold. 